This invention relates generally to vehicle headliners and, more particularly, to a headliner having impact protection for vehicle passengers.
Safety measures for vehicle passengers in the event of an impact have become more comprehensive. Federal regulations have become increasingly more stringent, especially regarding energy absorption of passenger head impact. For example, the Laboratory Test Procedure for FMVSS 201 requires that future passenger cars and other light vehicles achieve a head impact energy absorption performance requirements as determined by the following:
The HIC(d) shall not exceed 1000 when calculated in accordance with the following formula:
HIC(d)=0.75446 (Free Motion Headform HIC)+164 HIC calculated by the following formula: ##EQU1## where t.sub.1 and t.sub.2 are any two points in time during the impact event separated by no more than a 36 millisecond time period, and a is the resultant acceleration at the head center of gravity (c.g.).
These new standards require that the structure above the vehicle beltline (bottom of glass) subject to occupant head impact be modified to meet these standards. Many materials were investigated for impact energy absorption, but were found to be too bulky and/or expensive for use in the confines of a modern vehicle interior, where space is a tightly-rationed commodity. In addition, it is necessary to retain a sufficient amount of sound absorption to provide a quiet environment inside an automobile.
Since space is limited, it is desirable to develop a material which can meet these stringent energy absorption standards and still provide sufficient sound isolation characteristics.